Only after the show is over, when there's a chance to sit and ponder the dying mother, the empty birthday party and the hidden infidelities, do Fosse's finer points eventually reveal themselves.

There’s nothing more frustrating than a locked box. Acclaimed Norwegian playwright Jon Fosse’s “Sa Ka La” clearly has something inside it — over the play’s brief running time, we frequently hear the subtext rattling around — but director/translator Sarah Cameron Sunde can’t, or won’t, open up Fosse’s family drama to show us what it is. Only after the show is over, when there’s a chance to sit and ponder the dying mother, the empty birthday party and the hidden infidelities, do Fosse’s finer points eventually reveal themselves like flowers finally shoving out through cracked gray concrete.

In fairness to Sunde, this concrete is not of her pouring: Fosse’s writing is Pinter-ish in its economy and in its sense of place (Norway), and Sunde’s task — finding exactly the right American English word for every carefully considered Norwegian word in the script — is frankly impossible. She could have counterbalanced the translation’s inevitable shortcomings with detailed direction, though, and that’s where the play trips up.

Best in the cast is Frank Harts as Johannes, one of two sons-in-law (the other is Henning, played by Raymond McAnally) having a party for their overbearing-but-sweet mother-in-law (Kathryn Kates). Mom has suffered a stroke and is slowly expiring in the hospital, attended by her daughters Nora (Marielle Heller) and Hilde (Birgit Huppuch).

In his first scene, Harts’ character discovers he and Henning have both been sleeping with the family’s closest friend, Trine (Anna Gutto). They agree she’s “quite a lady,” and Gutto lives up to expectations — her Trine is dishy and innocent without affectations. Added to this, everyone is worried Mom’s only son Ola (Noel Joseph Allain) will show up.

And then nothing happens.

The party continues uninterrupted, despite the efforts of Hilde and Nora; Mom edges closer to death; Trine and her husband Karsten (Mike Caban) enter and make uncomfortable small talk. Mom makes noises that can’t be translated or understood. The inevitable takes place. The play ends.

The next morning, some scattered epiphanies might start to bloom in your imagination: Hilde and Nora’s efforts to communicate Mom’s dying state to Henning and Johannes bear a striking resemblance to Mom’s efforts to communicate… well, something to Hilde and Nora. Like the sisters, Karsten can sense there’s something amiss when Trine giggles too loudly at Henning’s jokes: It’s a sound that communicates a state of abnormality, but it’s not communication, so Karsten is as frustrated as Mom’s daughters when they hear her say “Sa! Ka! La!”

And, in the production’s crowning irony, it’s the way we in the audience feel as the play progresses without us, speaking and sometimes shouting in familiar-sounding words clearly meant to communicate a state of urgency — words that, ultimately, can’t travel that space between the mouth and the ear quickly enough to keep us engaged.

Sa Ka La

45 Bleecker; 90 seats; $19 top

Production

An Oslo Elsewhere presentation of a play in one act by Jon Fosse. Directed and translated by Sarah Cameron Sunde.